Herpes-like Virus Research Articles

Guinea pig herpes like virus is a gamma herpesvirus

Guinea Pig Herpes-Like Virus (GPHLV) is a virus isolated from leukemic guinea pigs with herpes virus-like morphology described by Hsiung and Kaplow in 1969. GPHLV transformed embryonic cells from Syrian hamsters or rats, which were tumorigenic in adult animals. Herein, we present the genomic sequence of GPHLV strain LK40 as a reference for future molecular analysis. GPHLV has a broad host tropism and replicates efficiently in Guinea pig, Cat, and Green African Monkey-derived cell lines. GPHLV has a GC content of 35.45%. The genome is predicted to encode at least 75 open-reading frames (ORFs) with 84% (63 ORFs) sharing homology to human Kaposi Sarcoma Associated Herpes Virus (KSHV). Importantly, GPHLV encodes homologues of the KSHV oncogenes, vBCL2 (ORF16), vPK (ORF36), viral cyclin (v-cyclin, ORF72), the latency associated nuclear antigen (LANA, ORF73), and vGPCR (ORF74). GPHLV is a Rhadinovirus of Cavia porcellus, and we propose the formal name of Caviid gamma herpesvirus 1 (CaGHV-1). GPHLV can be a novel small animal model of Rhadinovirus pathogenesis with broad host tropism.

A novel herpes-like virus inducing branchial lesions in a tiger shark (Galeocerdo cuvier).

A juvenile, male tiger shark (Galeocerdo cuvier) developed illness after capture in Florida waters and was euthanized. Gross lesions included mild skin abrasions, hepatic atrophy, and coelomic fluid. Histologically, gills contained multifocal lamellar epithelial cell necrosis and thromboses. Scattered gill and esophageal epithelial cells had large, basophilic, intracytoplasmic, and intranuclear inclusions. Ultrastructurally, lamellar epithelial cells contained arrays of intracytoplasmic viral particles and scattered intranuclear nucleocapsids. Capsulated virions were 148 ± 11 nm with an 84 ± 8 nm icosahedral nucleocapsid and an electron-dense core. Next-generation sequencing, quantitative polymerase chain reaction, and in situ hybridization performed on formalin-fixed tissue confirmed a herpes-like viral infection. The viral polymerase shared 24% to 31% protein homology with other alloherpesviruses of fish, indicating a divergent virus. This report documents the pathologic findings associated with a molecularly confirmed novel herpes-like virus in an elasmobranch.

Detection of viruses in abalone tissue using metagenomics technology

Abalone (Haliotis diversicolor) is an important marine and mariculture food resource that has been severely affected by several viral disease outbreaks in recent years, and the virus causing the disease has not been unequivocally identified. To establish viral metagenomic research protocols for H. diversicolor, we applied differential centrifugation and sucrose gradient ultracentrifugation to obtain virus-like particles from crude tissue extracts. After nuclease treatment to remove host nucleic acid, reverse transcription, and double-stranded amplification, we used the HiSeq 2500 platform to generate a viral genome dataset. A total of 6,055,591,750 nucleotides were produced from 24,222,367 reads, generating 65,382 contigs, with a total sequence length of 14,239,389 bp. We analysed and evaluated the sequence data by quality control mapping, among other methods and the results indicated good quality data. Alignment of the data with sequences in the GenBank virus database identified homology with a large number of Abalone Herpes-like Virus (AbHV) and Shriveling Syndrome-associated Virus (AbSV) sequences, and also a certain amount of White Spot Syndrome Virus (WSSV) sequences.

Green crab Carcinus maenas symbiont profiles along a North Atlantic invasion route

The green crab Carcinus maenas is an invader on the Atlantic coast of Canada and the USA. In these locations, crab populations have facilitated the development of a legal fishery in which C. maenas is caught and sold, mainly for use as bait to capture economically important crustaceans such as American lobster Homarus americanus. The paucity of knowledge on the symbionts of invasive C. maenas in Canada and their potential for transfer to lobsters poses a potential risk of unintended transmission. We carried out a histological survey for symbionts of C. maenas from their native range in Northern Europe (in the UK and Faroe Islands), and invasive range in Atlantic Canada. In total, 19 separate symbiotic associations were identified from C. maenas collected from 27 sites. These included metazoan parasites (nematodes, Profilicollis botulus, Sacculina carcini, Microphallidae, ectoparasitic crustaceans), microbial eukaryotes (ciliates, Hematodinium sp., Haplosporidium littoralis, Ameson pulvis, Parahepatospora carcini, gregarines, amoebae), bacteria (Rickettsia-like organism, milky disease), and viral pathogens (parvo-like virus, herpes-like virus, iridovirus, Carcinus maenas bacilliform virus and a haemocyte-infecting rod-shaped virus). Hematodinium sp. were not observed in the Canadian population; however, parasites such as Trematoda and Acanthocephala were present in all countries despite their complex, multi-species lifecycles. Some pathogens may pose a risk of transmission to other decapods and native fauna via the use of this host in the bait industry, such as the discovery of a virus resembling the previously described white spot syndrome virus (WSSV), B-virus and 'rod-shaped virus' (RV-CM) and amoebae, which have previously been found to cause disease in aquaculture (e.g. Salmo salar) and fisheries species (e.g. H. americanus).

Real-time isothermal detection of Abalone herpes-like virus and red-spotted grouper nervous necrosis virus using recombinase polymerase amplification

Abalone herpes-like virus (AbHV) and Red-spotted grouper nervous necrosis virus (RGNNV) are two serious viruses that infect animal populations in aquaculture. Both viruses cause diseases associated with high mortality rates, resulting in dramatic economic losses in the aquaculture industry. There are currently no effective treatments for either of these two viral diseases. Thus, early, rapid, and accurate diagnosis plays a fundamental role in disease prevention and control in aquaculture. Traditional methods of diagnosis, such as virus culture, enzyme-linked immunoassay, and polymerase chain reaction (PCR), are either time consuming or require sophisticated temperature control devices. In this study, one sets of specific primers and probes were designed for the real-time quantitative recombinase polymerase amplification (qRPA) detection of AbHV and RGNNV separately. The sensitivity and specificity of detection were evaluated by comparison with detection by conventional PCR and quantitative PCR. The optimal reaction temperature and time for virus detection is 37°C for 20min. The detection limit is 100 copies per reaction, making this approach faster and more sensitive than qPCR in this study. In a field application, the detection percentage of qRPA was higher than that of qPCR for both AbHV and NNV. Additionally, good correlation was found between qRPA and qPCR detection (R2>0.8). The methods presented here can be used as alternatives to qPCR for quick and quantitative detection of pathogens infecting aquaculture species.

Experimental infection of king crab hemocytes with a herpes-like virus in culture

To date, herpes-like viruses have been repeatedly found in wild king crab populations. In this study, freshly collected hemocytes of the red king crab Paralithodes camtschaticus have been experimentally exposed in culture to the herpes-like virus from thawed antennal gland samples from infected blue king crabs P. platypus. After 3–4 months of cultivation, significant differences in the pigmentation were observed between control and virus-infected hemocytes. Using Raman spectroscopy, we detected two obligatory peaks, characteristic for melanin identification, in the spectra of pigmented inclusions in harvested virus-infected hemocytes. These peaks are absent in the spectra obtained from control hemocytes. The cells of virus-infected cultures were viable after 10 months, while all control uninfected hemocytes were lost. As demonstrated by electron microscopic studies, virus-like particles become abundant at 7 days post-inoculation. Our results suggest that hemocytes could be used as a suitable model system for studies of crab pathogens. The in vitro studies confirm previous findings regarding the presence of viral infection in the natural population of king crabs.

Identification and rapid diagnosis of the pathogen responsible for haemorrhagic disease of the gill of Allogynogenetic crucian carp

In recent years, an epizootic causing severe mortality among Allogynogenetic crucian carp (ACC), designated as haemorrhagic disease of ACC gill, occurred in Yancheng city of Jiangsu province of China. Obvious haemorrhage in the gills of moribund fish and a mortality rate of 100% were observed when ACCs were artificially infected with liver homogenate from diseased fish. A herpes-like virus, with enveloped virions ranged from 170 to 220nm in diameter, could be observed in the tissues of challenged ACCs by examination with electron microscopy. Specific products representing the polymerase and helicase genes of Cyprinid herpesvirus-2 (CyHV-2) could be amplified from the challenged fish, suggesting that the haemorrhagic disease of ACC gill was caused by infection with CyHV-2. To rapidly diagnose CyHV-2-infected fish, an easy and effective detection assay with loop-mediated isothermal amplification (LAMP) was established. The LAMP assay was more sensitive than conventional PCR and the limit of detection was approximately 100 copies of target DNA. With this LAMP assay, CyHV-2 could be detected in some asymptomatic ACCs from the epidemic area and in eggs from the diseased ACCs, suggesting that CyHV-2 could infect ACCs latently and that the virus may be passed onto offspring by vertical transmission.

A herpes-like virus in king crabs: Characterization and transmission under laboratory conditions

A herpes-like virus was found infecting the antennal gland and bladder epithelium in the blue king crab Paralithodes platypus from the eastern area of the Sea of Okhotsk. Electron microscopic analysis of antennal gland samples from blue king crabs with histologically confirmed signs of disease revealed virus particles, which were mostly hexagonal in shape and located primarily in the nucleus; these particles were rarely observed in the cytoplasm of infected cells. Most virus particles ranged in size from 115 to 125nm. Hemocytes of the red king crab Paralithodes camtschaticus in cell culture could be experimentally infected with virus from thawed antennal gland samples of the blue king crabs with histologically confirmed signs of viral infection. Clear signs of infection were observed in hemocyte cultures at 3–4days post-inoculation as small foci of highly vacuolated formations. These formations included several nuclei and were surrounded by a halo of small cytoplasmic bubbles containing actin and tubulin. As demonstrated by electron microscopic studies, no virus-like particles were found in the cells 1day post-inoculation, but particles become abundant at 7days post-inoculation. We developed a consensus primer PCR method for amplification of a region of the herpesviral DNA-directed DNA polymerase. Primers were designed to target sequences encoding highly conserved amino acid motifs covering a region of approximately 800bp. Thus, macroscopic, histological and ultra-structural examinations of blue king crabs infected with a virus and the molecular identification of the pathogen revealed the presence of herpesviruses. The frequency of the herpes-like viral infection in natural populations of blue king crabs in the Sea of Okhotsk ranged from 0% to 3% in different years.

Sequence variation in ostreid herpesvirus 1 microvar isolates detected in dying and asymptomatic Crassostrea angulata adults in the Iberian Peninsula: Insights into viral origin and spread

The Portuguese oyster Crassostrea angulata was the main oyster species produced in Europe until the 1970s when mass mortalities almost led to its disappearance. At that time, mortality events were associated with detection of irido-like viruses and no record of herpes-like virus exists. Nowadays, C. angulata is only present in relatively few locations in the Iberian Peninsula, unlike in Asia where production is widespread. In 2011 and 2013, we observed mortality outbreaks of C. angulata adults collected in the Ria Formosa (Portugal) with a cumulative mortality of 47 and 59%, respectively, a few days after the oysters were transferred to indoor conditions. Ostreid herpesvirus 1 (OsHV-1) DNA was detected by PCR in all dying oysters analyzed and a high viral load was observed by real time PCR. Sequence analysis of ORFs 4, 42, 43 and 88 as well as a non-coding region near ORF4 revealed that the OsHV-1 genotype was the microvar (μvar) variant. No nucleotide sequence variation was observed in the regions analyzed in any of the 18 isolates. However, polymorphism was observed in a non-coding region (NC1/NC2 region) located between ORFs 49 and 50. Two genotypes in the NC1/NC2 region differing by several nucleotides were identified during the 2 mortality outbreaks and each genotype was unique to each mortality event. In addition, a third genotype in the NC1/NC2 region of OsHV-1 μvar was observed in asymptomatic adults of C. angulata collected in Carrera River (Spain). OsHV-1 DNA was not detected by PCR in any of the oysters collected in Sado and Mira estuaries. The results obtained in the present study suggest that the NC1/NC2 region may be a highly polymorphic region and hence of particular interest for molecular epidemiological studies. In light of the results of the present and previous studies on the genetic diversity and detection of OsHV-1 in C. angulata, we hypothesize that the virus was introduced recently in Europe from Asia, possibly with the introduction of C. gigas in the 1970s or soon after.

The histo- and ultra-pathological studies on a fatal disease of Prussian carp (Carassius gibelio) in mainland China associated with cyprinid herpesvirus 2 (CyHV-2)

Instead of the usual host, the goldfish, cyprinid herpesvirus 2 (CyHV-2), has been detected in the Prussian carp (Carassius gibelio) from Hungary, the Czech Republic and mainland China in recent years, which has caused the massive mortality of C. gibelio and appears to be spreading worldwide. From May to July of 2011 and 2012, the massive mortality of C. gibelio was observed in many aquatic breeding ponds in northern Jiangsu province, eastern China. Moribund fish showed petechial and eccymotic hemorrhages in gills and around the base of the fins and white color of fins. Histological examination revealed that tissues from gill, kidney and spleen presented symptoms of infiltration of hemocytes and the lesions. Transmission electron microscopy of these cells demonstrated naked herpes-like virus nucleocapsids (95–110nm) in their nuclei, while the cytoplasm contained multiple aggregates of enveloped viral particles (170–200nm). CyHV-2 infected gill, kidney and spleen and multiplied or enveloped in both nucleus and cytoplasm of leukocytes or hematopoietic cells. Maturation of CyHV-2 occurred in the cytoplasm, particularly associated with Golgi apparatus, indicating that the virus from C. gibelio probably contains viral glycoproteins. PCR method was used for detecting the virus by using CyHV-2 primers and produced positive results in the tissues of gill, kidney and spleen but negative results in the fins, liver and intestine, which coincided with histological and morphological results. The present work presents the ultrastructural pathology of this serious disease in C. gibelio caused by CyHV-2. It will be helpful to further understand the mechanism of CyHV-2 infection of this new fish host.

Coral as a model to study intrinsic and innate immune responses to herpes-like viruses (P6081)

Abstract Porites corals have been shown to produce herpes-like viruses when triggered by environmental stressors. We intend to use coral as a model species to study the immune responses to herpes-like viruses in an invertebrate species. The long-term goals of our study include measuring virus production in multiple coral species, determining if virus production increases under stress, and identifying possible immune genes in corals expressed in response to virus production. One frag of Porites and one of Acropora were grown in separate tanks, each containing artificial seawater and live rock. Stabilization of the corals was achieved through the use of timed overhead lighting, regular feeding, weekly testing of the water for calcium and dKH levels, and periodic addition of KH and magnesium. Two DNA extractions were done on each coral sample and used for PCR. Four genes are initially being targeted: ND5, a control; Spondin2, a putative immune gene; Hsp16, a stress gene; and Thymidylate synthase, produced by the herpes-like virus identified in Porites. Standard PCR has been effective at amplifying these sequences from genomic DNA. After optimization of PCR conditions and product sequencing, qPCR protocols will be developed to quantify gene expression. Future experiments will test the utility of measuring immune dysfunction as a leading indicator of coral reef stress.

Cloning and Expression of ORF124 Koi Herpesvirus as a Vaccine

Koi herpesvirus (KHV) which also known as Cyprinid herpesvirus 3 (CyHV-3), Koi herpes-like virus,and carp interstitial nephritis gill necrosis virus (CNGV), caused signifi cant morbidity and mortality in koiand common carp (Cyprinus carpio). The case fatality rate of this disease is 80–100%. Glycoprotein has beenused for vaccine development as sub unit vaccine against viruses. The aim of this research was to clone andexpress membrane glycoprotein ORF124 KHV as a candidate of recombinant vaccine. ORF124 KHV gene wassuccessfully cloned into pBSKS and sequenced. Result showed that ORF124 KHV (isolate from Indonesia) had100 % similarity with Cyprinid herpesvirus 3 strain TUMST1 (from Japan), 99% similarity with Koi herpesvirus strain KHV-U (from USA) and Koi herpesvirus strain KHV-I (from Israel). Prediction analysis of T and B cellepitopes showed that ORF124 KHV protein had 14 and 11 T cell epitopes (IAd, Rothbard/Taylor pattern),and had 10 B cell epitopes, suggested that the protein can be used as a vaccine candidate. ORF124 gene hasbeen expressed in Escherichia coli under pET32-a(+)vector.

Leucopenia associated with abalone viral ganglioneuritis

To compare microscopic lesion severity with circulating total haemocyte counts (THC) in abalone affected by abalone viral ganglioneuritis (AVG). A herpes-like virus led to severe mortality in a number of Australian abalone farms in 2006. The infection was associated with severe necrotising ganglioneuritis. The microscopic lesions were well demarcated, affecting the neural tissue almost exclusively and were characterised by necrosis and increased cellularity in affected ganglia and nerves. On two farms, the presence or absence of typical AVG pathology was compared with THC. Those abalone with microscopic lesions of AVG had significantly lower haemocyte counts. The mean THC in abalone with no evidence of AVG from both farms was 4.6 × 10(6)/mL (±0.3 SE). The THC in AVG-affected abalone in farm 1 was 2.8 × 10(6)/mL (±0.5 SE) and farm 2 was 0.98 × 10(6)/mL (±0.4 SE). Severe AVG is associated with leucopenia in affected abalone.

Herpes-like Virus Infection in Yangtze Finless Porpoise (Neophocaena phocaenoides): Pathology, Ultrastructure and Molecular Analysis

A moribund juvenile Yangtze finless porpoise (Neophocaena phocaenoides) with skin lesions and ulceration was found in Dongting Lake, China. Pathologic examination, electron microscopy, and polymerase chain reaction of liver tissue revealed widely distributed necrotic lesions, sinusoidal dilatation, congestion and herpes-like virus particles.

Development and validation of a TaqMan® PCR assay for the Australian abalone herpes-like virus

The recent emergence of a herpes-like virus in both farmed and wild populations of abalone in Victoria, Australia, has been associated with high mortality rates in animals of all ages. Based on viral genome sequence information, a virus-specific real-time TaqMan assay was developed for detection and identification of the abalone herpes-like virus (AbHV). The assay was shown to be specific as it did not detect other viruses from either the Herpesvirales or the Iridovirales orders which have genome sequence similarities. However, the TaqMan assay was able to detect DNA from the Taiwanese abalone herpes-like virus, suggesting a relationship between the Taiwanese and Australian viruses. In addition, the assay detected < 300 copies of recombinant plasmid DNA per reaction. Performance characteristics for the AbHV TaqMan assay were established using 1673 samples from different abalone populations in Victoria and Tasmania. The highest diagnostic sensitivity and specificity were 96.7 (95% CI: 82.7 to 99.4) and 99.7 (95% CI: 99.3 to 99.9), respectively, at a threshold cycle (C(T)) value of 35.8. The results from 2 separate laboratories indicated good repeatability and reproducibility. This molecular assay has already proven useful in confirming presumptive diagnosis (based on the presence of ganglioneuritis) of diseased abalone in Victorian waters as well as being a tool for surveillance of wild abalone stocks in other parts of Australia.

Partial genome analysis of Siberian sturgeon alloherpesvirus suggests its close relation to AciHV-2 — Short communication

Partial genome sequence of a herpes-like virus, isolated from Siberian sturgeon (Acipenser baeri), was determined and subjected to phylogenetic analysis. The virus (SbSHV) has been shown to be the causative agent of an acute disease with high mortality in farmed juvenile sturgeons in Russia. Two fragments (of 7000 and 300 base pairs in length) encompassing 3 complete and 3 partial ORFs were amplified by PCR. Sturgeon herpesvirus strains, classified into species Acipenserid herpesvirus 2 (AciHV-2), have been isolated and partially sequenced from several regions (California, Idaho, Oregon and Canada) of North America from white (A. transmontanus) and shortnose sturgeons (A. brevirostrum). The sequence of the SbSHV strain shared highest identity with that of the Canadian strain originating from shortnose sturgeon. The phylogenetic analysis also confirmed that SbSHV is closely related to AciHV-2 and could also be classified into this virus species. This is the first report on the occurrence of AciHV-2 in Europe. Previously, only another virus species, AciHV-1 has been detected in farmed white sturgeons in Italy. The size and position of ORFs in the examined gene block confirmed that this genomic region is highly conserved in members of the genus Ictalurivirus.

Gill erosion and herpesvirus in Crassostrea gigas cultured in Baja California, Mexico

Recurrent episodes of mortality of Crassostrea gigas cultured in northwestern Mexico have been occurring since 1997. Previous studies on bacteria, protozoans, and metazoans as presumptive causal agents have been inconclusive. However, erosions in the marginal indentation of gills have been frequently observed in oysters from areas affected by mortality events, and in 2000 those lesions were associated with the detection of a herpes-like virus. The present study aimed to describe the histological alterations of eroded gills and to determine whether ostreid herpesvirus 1 (OsHV-1) or a related virus was associated with them using in situ hybridization (ISH). Histology showed that gill filaments were fused. In severe cases, deformation of the interlamellar junctions, swelling, and the loss of water channels was observed. ISH analysis revealed the presence of OsHV-1 DNA or a related virus in cells of the gills. Some labeled cells were large with dark granules inside their cytoplasm. These cells were surrounded by infiltrating hemocytes. Some cells interpreted as hemocytes were labeled and observed in eroded and non-eroded areas of the gill. Large cells detected by ISH were also observed by conventional histology with hematoxylin-eosin staining. Whether the virus produces the erosions in the gills, or the erosions in the gills are produced by an unknown condition and favor the presence of the virus, remains unresolved. It is also not clear whether the lesions contribute to mortality.

Viral encephalitis of tilapia larvae: Primary characterization of a novel herpes-like virus

We report here an outbreak of an acute disease that caused high mortality rate in laboratory-reared tilapia larvae. The disease was initially observed in inbred gynogenetic line of blue tilapia larvae (Oreochromis aureus) and could be transmitted to larvae of other tilapia species. Based on the clinical manifestation (a whirling syndrome), we refer to the disease as viral encephalitis of tilapia larvae. The disease-associated DNA virus is described and accordingly designated tilapia larvae encephalitis virus (TLEV). A primary morphological, biophysical and molecular characterization of TLEV is presented. By virtue of these properties, the newly discovered virus is a herpes-like virus. Phylogenetic analysis, albeit limited, confirms this assumption and places TLEV within the family of Herpesviridae and distantly from the families Alloherpesviridae and Iridoviridae. By using PCR with virus-specific primers, diseased larvae and adult TLEV carriers were also identified in tilapia delivered from external hatcheries.

Detection of viruses and virus-like particles in four species of wild and farmed bivalve molluscs in Alaska, USA, from 1987 to 2009

The U.S. Alaska Department of Fish and Game has regulatory oversight of the mariculture industry that is partially administered through a statewide shellfish health policy. Possession and transport of bivalve molluscs require development of indigenous pathogen histories from diagnostic examinations of wild and farmed populations. These examinations have resulted in the detection of various infectious agents and parasites including viruses: an aquareovirus and aquabirna-like virus isolated by fish cell culture, and papilloma- or polyoma- and herpes-like virus particles within bivalve cell intranuclear inclusion bodies observed by electron microscopy. This study summarizes these results in samples examined from 1987 to 2009 and is the first description of poikilothermic viruses from Alaskan waters isolated from or observed within the tissues of 4 species of bivalve molluscs: geoduck clam Panope abrupta, native littleneck clam Protothaca staminea, purple-hinged rock scallop Crassadoma gigantea and Pacific oyster Crassostrea gigas.

Epidemiological features of Turkish patients with sarcoidosis

Epidemiological characteristics of sarcoidosis differ according to geographical distribution. The aim of our study was to disclose epidemiological characteristics in our country. The data was collected from investigators, who sent information on newly-diagnosed patients via internet. In 2 years 198 female and 95 male patients were enrolled to the study (f/m:2.08). Mean age of patients was 44+/-13 years (17-90). Mean age of male patients was 38+/-12 while mean age of female patients was 48+/-13 (p<0.001). 73.4% of patients were nonsmokers (85.4% of females; 48.4% of males; (p<0.001)). About 50% of our 293 patients were housewives. Familial sarcoidosis was found in 3 patients' first degree relatives. Estimated annual incidence of sarcoidosis for Turkey was calculated as 4 per 100,000 person. According to our study, 2/3 of sarcoidosis patients were women; mean age of patients was 45 and the disease began 10 years later in female patients. 80% of patients were nonsmokers; negative relation between sarcoidosis and smoking was evident especially in women. Familial sarcoidosis frequency was lower compared to other studies in the literature. There was no occupational exposure history in our patients. Our incidence rate, is similar with the results of other European studies.